甲基丙烯酸甲酯可逆加成—断裂链转移聚合动力学

Kinetics of methyl methacrylate reversible addition-fragmentation chain transfer polymerization

甲基丙烯酸甲酯(MMA)是制备不同结构和性能聚合物的重要成分之一。为了研究MMA的可逆加成—断裂链转移聚合动力学等相关参数,合成了苯甲酸-2-腈基异丙基二硫代酯(CPDB)为RAFT试剂进行本体和细乳液聚合。在本体和细乳液聚合中,CPDB浓度越高,聚合速率越低,其中细乳液"缓聚"现象明显;聚合指数-ln(1-x)与聚合时间呈较好的线性关系,具有可控/"活性"聚合的特征;聚合物的数均分子量Mn随转化率线性增加,分子量分布宽度PDI随着CPDB浓度的增加,分布逐渐变窄等。同时,在细乳液聚合中,CPDB浓度增加,乳胶粒粒径越大,分布也越宽,聚合速率也越低等。

Methyl methacrylate（MMA） was an important ingredient for different structures and properties of copolymers.In order to study MMA reversible addition-fragmentation chain transfer（RAFT） polymerization kinetics,bulk and miniemulsion for MMA polymerization were performed with 2-cyanoprop-2-yl dithiobenzoate（CPDB） as RAFT agent.The conversion decreased with increasing CPDB concentration in bulk and miniemulsion system,and the retardation was more obvious in miniemulsion than in bulk system.The linear relationship between the polymerization index-ln（1-x） and the polymerization time was good,which has the controlled/＂living＂polymerization characteristics.The Molucular weight of PMMA in bulk and miniemulsion systems increased linearly,and its distribution became much narrower along with the increasing of conversion,when CPDB concentration increased.Moreover,the particle size increased with CPDB concentration increaseing in miniemulsion,and the distribution became much broader.